Composite article and support frame assembly

ABSTRACT

A support frame includes a rail engaging a hook of a composite article having plys. The rail included a rail contact surface generally conformal to and contacting a hook contact surface of the hook. The rail and hook contact surfaces being substantially normal to the plys beneath the hook contact surface. One embodiment of the article is a composite nozzle segment including one or more airfoils extending radially between arcuate radially outer and inner band segments having plys curved about a centerline axis and the rail engages a hook of the radially inner band segment. The hook and the rail may be straight or arcuate. The frame includes a central body extending axially aftwardly from the rail to an aft frame flange. A frame pin may be mounted on the frame, engage the inner band segment or one of the airfoils, and may extend into a cavity in the airfoil.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to support of composite articles having plys and,more particularly, to the support of composite turbine nozzles.

2. Description of Related Art

A typical gas turbine engine of the turbofan type generally includes aforward fan and a booster or low pressure compressor, a middle coreengine, and a low pressure turbine which powers the fan and booster orlow pressure compressor. The core engine includes a high pressurecompressor, a combustor and a high pressure turbine in a serial flowrelationship. The high pressure compressor and high pressure turbine ofthe core engine are connected by a high pressure shaft. High pressureair from the high pressure compressor is mixed with fuel in thecombustor and ignited to form a high energy gas stream. The gas streamflows through the high pressure turbine, rotatably driving it and thehigh pressure shaft which, in turn, rotatably drives the high pressurecompressor.

The gas stream leaving the high pressure turbine is expanded through asecond or low pressure turbine. The low pressure turbine rotatablydrives the fan and booster compressor via a low pressure shaft. The lowpressure shaft extends through the high pressure rotor. Most of thethrust produced is generated by the fan. Marine or industrial gasturbine engines have low pressure turbines which power generators, shippropellers, pumps and other devices while turboprops engines use lowpressure turbines to power propellers usually through a gearbox.

The high pressure turbine has a turbine nozzle which is usuallysegmented and includes an annular ring or row of turbine nozzlesegments. Each segment includes circumferentially spaced apart airfoilsradially extending between radially inner and outer bands. The airfoilsare usually hollow having an outer wall that is cooled with cooling airfrom the compressor. Hot gases flowing over the cooled turbine vaneouter wall produces flow and thermal boundary layers along outersurfaces of the vane outer wall and end wall surfaces of the inner andouter bands over which the hot gases pass.

Conventional segments have been made of metal and, more recently,designs have been developed incorporating composite material for partsof or all of the segments. Composite materials offer greater thermalprotection and allow the turbine to operate at higher temperatures andreduce the amount of cooling air. These lead to improved component lifeand engine efficiency.

The composite materials are made of plys. Composite material nozzles andcomposite articles in general are somewhat brittle as compared to theirmetallic counterparts. First stage high pressure turbine nozzle segmentsare frequently simply supported at both the inner and outer ends. Sincethe two supports move relative to each other due to changing engineconditions and, thus, the nozzle segment must be able to rock and sliderelative to the supports to remain in contact with both. A high pressuredrop exists across contact areas between the nozzle and the supportsduring engine operation making it difficult to maintain contact withoutinducing concentrated stresses in the segment. Stresses are particularlydetrimental to composite material components of the turbine nozzle andits segments.

The nozzle bands are arcuate to conform to the annulus of the engine. Anarc shaped contact between the band and support creates an uneven loaddistribution as the nozzle rocks and opens large leakage areas. At theinner band, especially the available space is small, the axial extentbeing limited by an adjacent turbine blade attachment. Metal turbinenozzles include a support rail typically cast as part of the nozzlesegment, approximately ¾ of the axial distance back from the leadingedge of the inner band or platform. This is machined to form a chordalhinge or chordal seal. The geometry local to the contact area is shapedsuch that the contact occurs along a straight line (chord). This allowsthe vane segment to rock without changing the load distribution orincreasing leakage.

A similar feature in a composite nozzle would result in the supportloads being carried in shear between plys in the band and result ininter-laminar tension where the rail attaches to the bands. The strengthin these loading directions is low for the intended material making thisapproach unsatisfactory. Such a design can also lead to delamination ofthe plys in the bands. It is desirable to provide a support forcomposite turbine nozzle segments and composite articles in general thateliminate or reduce support loads being carried in shear between plys.More particularly, it is desirable to provide a support for compositeturbine nozzle segments that eliminate or reduce support loads beingcarried in shear between plys in the bands of composite turbine nozzlesegments.

SUMMARY OF THE INVENTION

A composite article and frame assembly includes a composite articlehaving plys, a support frame including a rail engaging a hook of thecomposite article, a rail contact surface on the rail generallyconformal to and contacting a hook contact surface of the hook, and therail and hook contact surfaces being substantially normal to the plysbeneath the hook contact surface. The hook and the rail may be straightor arcuate. The composite article may be a composite nozzle segmentincluding one or more hollow airfoils extending radially betweenradially outer and inner band segments and the outer and inner bandsegments being arcuate and curved about a centerline axis.

A composite nozzle segment and frame assembly includes a compositenozzle segment including one or more hollow airfoils extending radiallybetween arcuate radially outer and inner band segments having plys andcurved about a centerline axis, a support frame including a railengaging a hook of the radially inner band segment, a rail contactsurface of the rail generally conformal to and contacting a hook contactsurface of the hook, and the rail and hook contact surfaces beingsubstantially normal to the plys beneath the hook contact surface.

The frame may include a central body extending axially aftwardly fromthe rail to an aft frame flange and a mounting flange extending radiallyinwardly from a forward position of the central body aft of the rail. Aframe pin or a tab may be mounted on the frame, engage the inner bandsegment or one of the airfoils, and extend into a cavity of the airfoil.The frame pin may be screwed into a threaded boss on the frame.

A clamped assembly may further include the frame clamped to thecomposite nozzle segment by a clamp having a threaded rod extendingthrough a cavity of one of the hollow airfoils. The rod may be screwedinto a threaded boss on the frame and have a load spreader attached to aradially outer end of the rod with a nut such that the load spreaderengages the outer band segment to clamp the frame to the compositenozzle segment.

A turbine nozzle and support assembly includes a circular row of thecomposite nozzle segments and each composite nozzle segment contacts aframe for transferring axial loads from the composite nozzle segment toan aft nozzle support. The frame may include a central body extendingaxially aftwardly from the rail to an aft frame flange having an aftfacing peaked surface. An axial load path extends axially through theframe to a support flange of the aft nozzle support.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other features of the invention are explainedin the following description, taken in connection with the accompanyingdrawings where:

FIG. 1 is a longitudinal, sectional view illustration of exemplaryembodiment of an aircraft gas turbine engine combustor and a compositeturbine nozzle of a high pressure turbine section of the engine.

FIG. 2 is an enlarged view of composite inner and outer bands andairfoil therebetween of the turbine nozzle illustrated in FIG. 1.

FIG. 3 is an enlarged cross-sectional view illustration of the innerband and its plies of the turbine nozzle illustrated in FIG. 1.

FIG. 4 is a circumferential perspective view illustration of thecomposite turbine nozzle segment and inner band support of the turbinenozzle illustrated in FIG. 2.

FIG. 5 is an aft looking forward perspective view illustration of thecomposite turbine nozzle segment and inner band support of the turbinenozzle illustrated in FIG. 2.

FIG. 6 is a forwardly and radially inwardly looking perspective viewillustration of two adjacent single turbine nozzle segments of theturbine nozzle illustrated in FIG. 2.

FIG. 7 is an aftwardly and radially inwardly looking perspective viewillustration of a doublet turbine nozzle segment.

FIG. 8 is an aftwardly and circumferentially looking perspective viewillustration of the doublet turbine nozzle segment illustrated in FIG.7.

FIG. 9 is an enlarged view of composite inner and outer bands andairfoil therebetween of the turbine nozzle illustrated in FIG. 1 with analternative aft support for the inner band.

FIG. 10 is a forward looking aft perspective view illustration of analternative embodiment of the composite turbine nozzle segmentillustrated in FIG. 2 with a frame with a straight chordal rail.

FIG. 11 is an aft looking forward perspective view illustration of thecomposite turbine nozzle segment and the frame illustrated in FIG. 10.

FIG. 12 is a cross-sectional view illustration of a composite turbinenozzle segment and frame clamped assembly.

FIG. 13 is an aft looking forward perspective view illustration of thecomposite turbine nozzle segment and frame assembly illustrated in FIG.12.

FIG. 14 is a cross-sectional view illustration of a insert plies inouter band of the turbine nozzle illustrated in FIG. 1.

FIG. 15 is a cross-sectional view illustration of interspersed insertplies in outer band of the turbine nozzle illustrated in FIG. 1.

FIG. 16 is a perspective view illustration of the insert plies along asuction side edge of the outer band of the turbine nozzle illustrated inFIG. 15.

FIG. 17 is a perspective view illustration of insert plies along apressure side edge of the outer band of the turbine nozzle illustratedin FIG. 15.

FIG. 18 is a diagrammatic view illustration of insert plies of insertsalong pressure and suction side edges of the outer band of the turbinenozzle illustrated in FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

Illustrated in FIG. 1 is an exemplary gas turbine engine combustor 10for generating combustion gases that are discharged to a high pressureturbine 38 downstream of the combustor 10 and used to drive a highpressure compressor (not shown) upstream of the combustor 10 throughsuitable shaft (not shown). A longitudinal or axial centerline axis 12is provided through the gas turbine engine and the combustor 10 forreference purposes. The combustor 10 includes a combustion chamber 14defined by a radially outer combustion liner 16, a radially innercombustion liner 18 and a dome 20 for supporting fuel/air mixers 21 withfuel nozzles (not shown) centrally supported therein.

Directly upstream of the dome 20 is a compressor discharge assembly 22that is structurally tied to a radially outer combustor casing 23 andstructurally supports a radially inner combustor casing 24. The outerand inner combustion liners 16, 18 are radially disposed between andaxially and radially supported by the outer and inner combustor casings23, 24.

A segmented first stage turbine nozzle 25 located directly downstream ofthe combustor 10 is circumscribed about the centerline axis 12 andprovided to direct the flow of combustion gases into the high pressureturbine 38. The segmented first stage turbine nozzle 25 is supported ona turbine shroud 231 or shroud hanger of the high pressure turbine 38.The turbine shroud 231 or shroud hanger is supported by a turbine casing36 attached to the outer combustor casing 23. A conical turbine support31 attached to the inner combustor casing 24 and provides radial andaxial support and locating of the first stage turbine nozzle 25.

Referring more particularly to FIGS. 1, 2, 6, and 7, the segmentedturbine nozzle 25 includes a circular row 9 of composite nozzle segments11 including one or more solid or hollow airfoils 28 extending radiallybetween integrally formed or joined radially outer and inner bandsegments 26, 27. The outer and inner band segments 26, 27 are arcuateand are curved about the centerline axis 12. Each of the airfoils 28includes pressure and suction sides 29, 30 extending axially betweenairfoil leading and trailing edges LE, TE and extending radially withrespect to the centerline axis 12, between airfoil base and tips, 40, 42at the inner and outer band segments 27, 26 respectively. The inner andouter band segments 27, 26 include segment leading and trailing edges44, 46 generally corresponding to the airfoil leading and trailing edgesLE, TE, respectively.

Composite nozzle segments 11 illustrated in FIGS. 4-6 have only oneairfoil 28 located between circumferentially spaced apart pressure andsuction side edges 33, 35 of the radially outer and inner band segments26, 27. FIGS. 7 and 8 illustrate an alternative configuration of thecomposite nozzle segment 11 having two airfoils 28 located betweencircumferentially spaced apart pressure and suction side edges 33, 35 ofthe radially outer and inner band segments 26, 27. The composite nozzlesegment 11 may have more than two airfoils. The composite nozzlesegments 11 illustrated herein are representative of composite articles15 in general that have plies 48 (illustrated in FIG. 3).

The airfoils 28 and the outer and inner band segments 26, 27 are madefrom plies 48 of material that distinctly remain in the airfoils 28 andthe outer and inner band segments 26, 27 as illustrated in FIG. 3 whichis an end view of the inner band segment 27. Further illustrated inFIGS. 2 and 3 is a hook 50 at the segment leading edge 44 of the innerband segment 27. The hook 50 is curved radially inwardly and axiallydownstream or aftwardly from the segment leading edge 44.

Referring to FIGS. 3 and 8, the hook 50 is illustrated herein as beingarcuate and circumscribed at a radius R about the centerline axis 12. Acurved inner surface 52 of the hook 50 is substantiallycircumferentially co-extensive with the segment leading edge 44 aboutthe axis 12. Alternatively, the hook 50 may be straight and tangentialto the radius R about the centerline axis 12, in which case, the hook 50may be described as being chordal and extending linearly between twocircumferentially spaced apart radii RR about the centerline axis 12 asillustrated in FIGS. 10 and 11.

Referring back to FIG. 2, a support frame 53 is used to transfer axialloads from the composite nozzle segment 11 to an aft nozzle support 56located radially inwardly of the inner band segment 27 and at a supportaft end 58 of the conical turbine support 31. The conical turbinesupport 31 is attached to the inner combustor casing 24 and used forproviding radial and axial support and locating of the first stageturbine nozzle 25. The composite nozzle segment 11 and the frame 53 arerepresentative of a composite article and frame assembly 13. The frame53 is slidably and pivotably restrained within the aft nozzle support56. Typically, the frame 53 and the aft nozzle support 56 and theconical turbine support 31 are made of metal. A rail 60 of the frame 53engages the hook 50 to transfer axial and radial loads from thecomposite nozzle segment 11 to the aft nozzle support 56.

Tangential or circumferential loads are reacted out through the frame 53by a frame pin 62 or tab mounted on the frame 53 and which engages theinner band segment 27 or the airfoil 28 as illustrated in FIGS. 2, 4,and 5. The frame pin 62 extends into a cavity 166, illustrated in FIG.5, for a hollow airfoil 28. External threads 172 on the frame pin 62provide for the frame pin 62 to be screwed into a threaded boss 168 onthe frame 53. A head 170 of the frame pin 62, located at a radiallyinner end 173 of the frame pin 62 engages an internally threaded boss168 in the frame 53 to secure the frame pin 62 in place. If the airfoil28 is not hollow then the frame pin 62 could be designed to engageanother feature such as a recess machined or molded into the inner bandsegment 27.

Referring to FIG. 2, the frame 53 extends axially aftwardly ordownstream from the rail 60 to an aft frame flange 70 and includes acentral body 76 therebetween. The aft frame flange 70 has an aft facingpeaked surface 100 that includes an apex 102 at its aftwardmost point.The apex 102 serves as pivot point so that the frame 53 can rock orpivot to accommodate uneven thermal growth between the outer and innercombustor casings 23, 24. The axial compressive loads are reacted outfrom the composite nozzle segment 11 to the aft nozzle support 56through the frame 53. The rail 60, the central body 76, and the aftframe flange 70 are arcuate and are curved and circumscribed atrespective radii RR about the centerline axis 12 as illustrated in FIG.8. The turbine nozzle 25 illustrated herein includes a seal retainer 110used to retain a ring seal 112 against a support flange 113 of the aftnozzle support 56 and the apex 102 of the frame 53 contacts the sealretainer 110. Thus, the axial compressive loads are reacted out from thecomposite nozzle segment 11 to the support flange 113 of the aft nozzlesupport 56 through an axial load path 116 through the frame 53, the sealretainer 110 and the ring seal 112 for the embodiment of the turbinenozzle 25 illustrated herein.

A mounting flange 74 extends radially inwardly from a forward position80 of the central body 76 just somewhat aft of the rail 60. The mountingflange 74 is used to radially support radially inner seal pins 84 thatsupport a flexible radially inner leaf seal 86 that seals between theinner band segment 27 and the inner combustion liner 18. An outerforward flange 90 of the radially outer band segment 26 is used toradially support radially outer seal pins 94 that support a flexibleradially outer leaf seal 96 that seals between the outer band segment 26and the outer combustor casing 23. The frame 53 is illustrated herein asbeing arcuate and is curved and circumscribed at a radius R about thecenterline axis 12 as illustrated in FIG. 8. The frame 53 may be flatand tangential to the radius R about the centerline axis 12, in whichcase, the frame 53 may be described as being chordal and extendinglinearly between two circumferentially spaced apart radii about thecenterline axis 12 as illustrated in FIG. 10.

As illustrated in FIGS. 2 and 3, the rail 60 has a rail contact surface64 that is generally conformal to and contacts a hook contact surface66. The rail and hook contact surfaces 64, 66 are substantially normalto the plies 48 beneath the hook contact surface 66. This allows theloads, compressive loads for embodiment of hook illustrated herein, tobe transferred in a direction along the plies instead of across theplies. The inner band segment 27 may be radially located or supported atan outer band aft end 68 of the inner band segment 27 on the aft frameflange 70 as illustrated in FIG. 2. Alternatively, the inner bandsegment 27 may be radially located or supported at the outer band aftend 68 of the inner band segment 27 on the aft frame flange 70 of theframe 53 as illustrated in FIG. 9.

Illustrated in FIGS. 10 and 11 is a flat frame 120 having a straight orchordal rail 122, a flat central body 124, and a straight or chordal aftframe flange 126. The composite nozzle segment 11 is generally the sameand includes one or more solid or hollow airfoils 28 extending radiallybetween integrally formed or joined radially outer and inner bandsegments 26, 27. The outer and inner band segments 26, 27 are arcuateand are curved about the centerline axis 12. Each of the airfoils 28includes pressure and suction sides 29, 30 extending axially betweenairfoil leading and trailing edges LE, TE and extending radiallyoutwardly, with respect to the centerline axis 12, between airfoil baseand tips, 40, 42 at the inner and outer band segments 27, 26respectively.

A straight or chordal hook 150 is located at the segment leading edge 44of the inner band segment 27. The chordal hook 150 is straight in thecircumferential direction with respect to the centerline axis 12 andcurved radially inwardly and axially downstream from the segment leadingedge 44. The inner band segment 27 transits from an arcuate shape to astraight shape to accommodate the chordal hook 150. An inner bandchordal seal 130 is thus formed between the chordal hook 150 and theinner combustor casing 24 along an inner chordal seal line 132 of thechordal hook 150. The mounting flange 74 is used to radially supportradially inner seal pins 84 that support a flexible radially inner leafseal 86 that seals between the inner band segment 27 and the innercombustor casing 24.

An outer band chordal seal 230 is formed between an outer aft flange 134of the outer band segment 26 and a turbine shroud 231 along an outerchordal seal line 232 on the outer aft flange 134 as illustrated inFIG. 1. Referring back to FIGS. 10 and 11, the outer chordal seal line232 passes through a linear or chordal contact area 237 of the outerband chordal seal 230 and the linear or chordal contact area 237 lies onthe outer aft flange 134. Alternatively, the outer band chordal seal 230may be formed between an outer aft flange 134 of the outer band segment26 and a turbine shroud hanger or other non-rotating static structurenear or adjacent the outer chordal seal line 232 on the outer aft flange134.

Illustrated in FIGS. 12 and 13 is a clamped frame and nozzle segmentassembly 160 in which the frame 53 is clamped to the composite nozzlesegment 11 by a clamp 162. The clamp 162 is illustrated herein as havinga threaded rod 164 extending through a cavity 166 of the hollow airfoil28. The rod 164 includes threads 172 which are screwed into a threadedboss 168 on the frame 53. A head 170 at a radially inner end 173 of therod 164 engages the threaded boss 168. A load spreader 174 is attachedto a threaded radially outer end 176 of the rod 164 with a nut 178. Theload spreader 174 engages the outer band segment 26 thus clamping theframe 53 to the composite nozzle segment 11.

Illustrated in FIGS. 14-18 are gradually thickened areas 221 of theouter band segment 26 near the outer aft flange 134 and the segmenttrailing edge 46 of the outer band segment 26 relative to a relativelyconstant unthickened area 223 of the outer band segment 26. Exemplaryembodiments of the thickened areas 221 are illustrated herein in corners222 of the outer aft flange 134 along the pressure and suction sideedges 33, 35 of the radially outer band segment 26. The thickened area221 is thickest at the pressure and suction side edges 33, 35 of theradially outer band segment 26 and thinnest near a middle 238 of theouter band segment 26 as illustrated in FIGS. 16-18. The thickened area221 tapers off in thickness T from an aft end 240 of the thickened area221 forwardly towards the forward flange 90 (illustrated in FIG. 10) ofthe radially outer band segment 26.

The outer band segment 26 is made up of band plies 248. A firstplurality of the band plies 248 are flowpath plies 252 which are closestto a flowpath 250 through the composite nozzle segment 11 between theouter and inner band segments 26, 27 (as illustrated in FIG. 10) andprimarily provide the flowpath geometry of the outer band segment 26. Asecond plurality of the band plies 248 are structural plies 254 that arefarthest from the flowpath 250 and provide primarily structural supportfor the outer band segment 26. The thickening of the segment trailingedge 46 of the outer band segment 26 enables the structural plies 254 toreact support loads in compression and prevents unwanted bending. Thethickening may be done by inserting insert plies 260 between the bandplies 248 within the thickened areas 221 of the outer band segment 26.The insert plies 260 are covered with covering plies 263 which are madeup of some outermost ones of the band plies 248 as illustrated in FIGS.14 and 15.

The insert plies 260 may be grouped together in a discrete group 262 asillustrated in FIG. 14. Alternatively, the insert plies 260 may bedistributed or interspersed with some of the band plies 248 and, moreparticularly, with some of the structural plies 254 as illustrated inthe exemplary embodiment of the thickened area 221 illustrated in FIG.15. The insert plies 260 have a generally triangular planform shapes Swith widths W that narrow from the pressure and suction side edges 33,35 towards the middle 238 of the outer band segment 26 as illustrated inFIGS. 16-18 in which covering plies 263 have been removed to facilitatein illustrating the insert plies.

FIGS. 16-18 also illustrate that the thickened areas 221 along thepressure and suction side edges 33, 35 of the outer band segment 26 maybe different. One of the thickened areas 221 may be larger both in widthW and chordal length CL and may be thicker than the other and have moreand larger insert plies 260 than the other. This is done to align theouter chordal seal line 232 on the outer aft flange 134 with the innerchordal seal line 132 of the chordal hook 150, which are angularlyoffset from each other about the centerline axis 12, so that they areparallel as illustrated in FIGS. 10 and 18.

As illustrated in FIGS. 14 and 15, the flowpath plies 252 may be wrappedaround an outer band aft end 270 of the structural plies 254 to form, atleast in part, the outer aft flange 134 of the outer band segment 26.The wrapped flowpath plies 252 provide a smooth contact surface 272along the inner chordal seal line 132 and protect aft ends 274 of thestructural plies 254 from environmental damage or abrasion anddelamination due to sliding contact with the turbine shroud 231(illustrated in FIG. 1) along the outer band chordal seal 230 betweenthe outer aft flange 134 and the turbine shroud 231 along the outerchordal seal line 232 of the outer aft flange 134.

The present invention has been described in an illustrative manner. Itis to be understood that the terminology which has been used is intendedto be in the nature of words of description rather than of limitation.While there have been described herein, what are considered to bepreferred and exemplary embodiments of the present invention, othermodifications of the invention shall be apparent to those skilled in theart from the teachings herein and, it is, therefore, desired to besecured in the appended Claims all such modifications as fall within thetrue spirit and scope of the invention.

1. A composite article and frame assembly comprising: a compositearticle having plys, a support frame including a rail engaging a hook ofthe composite article, the rail including a rail contact surfacegenerally conformal to and contacting a hook contact surface of thehook, and the rail and hook contact surfaces being substantially normalto the plys beneath the hook contact surface.
 2. An assembly as claimedin claim 1, further comprising the hook and the rail being straight. 3.An assembly as claimed in claim 1, further comprising the hook and therail being arcuate.
 4. An assembly as claimed in claim 1, furthercomprising the composite article being a composite nozzle segmentincluding one or more airfoils extending radially between radially outerand inner band segments and the outer and inner band segments beingarcuate and curved about a centerline axis.
 5. A composite nozzlesegment and frame assembly comprising: a composite nozzle segmentincluding one or more airfoils extending radially between arcuateradially outer and inner band segments having plys and curved about acenterline axis, a support frame including a rail engaging a hook of theradially inner band segment, the rail including a rail contact surfacegenerally conformal to and contacting a hook contact surface of thehook, and the rail and hook contact surfaces being substantially normalto the plys beneath the hook contact surface.
 6. An assembly as claimedin claim 5, further comprising the hook and the rail being straight. 7.An assembly as claimed in claim 5, further comprising the hook and therail being arcuate.
 8. An assembly as claimed in claim 5, furthercomprising: each of the airfoils including pressure and suction sidesextending axially between airfoil leading and trailing edges andextending radially between the inner and outer band segments, the innerand outer band segments including segment leading and trailing edgesgenerally corresponding to the airfoil leading and trailing edgesrespectively, and the hook being located at the segment leading edge ofthe inner band segment and curved radially inwardly and axiallyaftwardly from the segment leading edge.
 9. An assembly as claimed inclaim 8, further comprising the hook and the rail being straight.
 10. Anassembly as claimed in claim 8, further comprising the hook and the railbeing arcuate.
 11. An assembly as claimed in claim 8, further comprisingthe frame including a central body extending axially aftwardly from therail to an aft frame flange.
 12. An assembly as claimed in claim 11,further comprising the frame including a mounting flange extendingradially inwardly from a forward position of the central body aft of therail.
 13. An assembly as claimed in claim 11, further comprising a framepin or a tab mounted on the frame and engaging the inner band segment orone of the airfoils.
 14. An assembly as claimed in claim 13, furthercomprising the frame pin having a threaded radially inner end screwedinto a threaded boss on the frame.
 15. An assembly as claimed in claim8, further comprising the frame clamped to the composite nozzle segmentby a clamp.
 16. An assembly as claimed in claim 15, further comprising:at least one of the airfoils being hollow and having a cavity, the clampincluding a threaded rod extending through the cavity, the rod includinga threaded radially inner end screwed into a threaded boss on the frame,and a load spreader attached to a threaded radially outer end of the rodwith a nut, and the load spreader engaging the outer band segment toclamp the frame to the composite nozzle segment.
 17. An assembly asclaimed in claim 16, further comprising the hook and the rail beingstraight.
 18. An assembly as claimed in claim 16, further comprising thehook and the rail being arcuate.
 19. An assembly as claimed in claim 16,further comprising the frame including a central body extending axiallyaftwardly from the rail to an aft frame flange.
 20. An assembly asclaimed in claim 19, further comprising the frame including a mountingflange extending radially inwardly from a forward position of thecentral body aft of the rail.
 21. A turbine nozzle and support assemblycomprising: a circular row of composite nozzle segments, each compositenozzle segment in the circular row of composite nozzle segmentscontacting a frame for transferring axial loads from the compositenozzle segment to an aft nozzle support, the composite nozzle segmentincluding one or more airfoils extending radially between arcuateradially outer and inner band segments having plys and curved about acenterline axis, the support frame including a rail engaging a hook ofthe radially inner band segment, the rail including a rail contactsurface generally conformal to and contacting a hook contact surface ofthe hook, and the rail and hook contact surfaces being substantiallynormal to the plys beneath the hook contact surface.
 22. An assembly asclaimed in claim 21, further comprising: the frame including a centralbody extending axially aftwardly from the rail to an aft frame flangehaving an aft facing peaked surface, a support flange of the aft nozzlesupport, and an axial load path through the frame to the support flange.23. An assembly as claimed in claim 22, further comprising the hook andthe rail being straight.
 24. An assembly as claimed in claim 22, furthercomprising the hook and the rail being arcuate.
 25. An assembly asclaimed in claim 22, further comprising: each of the airfoils includingpressure and suction sides extending axially between airfoil leading andtrailing edges and extending radially between the inner and outer bandsegments, the inner and outer band segments including segment leadingand trailing edges generally corresponding to the airfoil leading andtrailing edges respectively, and the hook being located at the segmentleading edge of the inner band segment and curved radially inwardly andaxially aftwardly from the segment leading edge.
 26. An assembly asclaimed in claim 25, further comprising the hook and the rail beingstraight.
 27. An assembly as claimed in claim 25, further comprising thehook and the rail being arcuate.
 28. An assembly as claimed in claim 25,further comprising the frame including a central body extending axiallyaftwardly from the rail to an aft frame flange.
 29. An assembly asclaimed in claim 28, further comprising a frame pin or a tab mounted onthe frame and engaging the inner band segment or one of the airfoils.30. An assembly as claimed in claim 29, further comprising the frame pinhaving a threaded radially inner end screwed into a threaded boss on theframe.
 31. An assembly as claimed in claim 25, further comprising theframe clamped to the composite nozzle segment by a clamp.
 32. Anassembly as claimed in claim 31, further comprising: at least one of theairfoils being hollow and having a cavity, the clamp including athreaded rod extending through the cavity, the rod including a threadedradially inner end screwed into a threaded boss on the frame, and a loadspreader attached to a threaded radially outer end of the rod with anut, and the load spreader engaging the outer band segment to clamp theframe to the composite nozzle segment.
 33. An assembly as claimed inclaim 32, further comprising the hook and the rail being straight or thehook and the rail being arcuate.